Closing Extra Windows
You want to keep the Info Editor at the top of your window.

You can resize it so that only the header is visible as most times that is all you will use.


Start by opening a new file.
move the cursor to the bottom of the info header until you get a double arrowed cursor, then drag up until only the header is visible.





Select File->Save Startup File. This is why you want to start with a new file, saving the startup file will keep this screen layout every time you start blender.


Note that any files you saved with the altered screen layout can be opened with that layout, disable the Load UI option to use your saved default layout. you can change the default Load UI option in your preferences.